Module resolver 

Transport-aware DNS resolver construction.

Both the validation pipeline and the dns query subcommand build Hickory resolvers from configured DNS endpoints. The resolver setup is identical for both surfaces; only the source of the configuration differs (legacy ValidationEndpointConfig for validation, the per-server [servers.dns|dot|doh|doq] blocks for query). This module provides:

• ResolverTarget: a small neutral struct holding everything a resolver build needs (transport, host, port, URL, SNI, timeout).
• Converters from legacy and new config shapes into a ResolverTarget.
• resolver_config / build_resolver: produce ResolverConfig / Resolver<TokioRuntimeProvider> from a target.
• classify_hickory_error: map Hickory error strings to stable ValidationFailureKind variants for downstream reporting.

DoQ support is gated behind the doq Cargo feature. On default builds, a target with ValidationTransport::Doq returns ValidationFailureKind::UnsupportedTransport.

Structs

ResolverTarget

Minimal data a resolver build needs, transport-tagged.

Enums

ResolverKind

Where a ResolverTarget was sourced from.

Constants

DEFAULT_TIMEOUT_MS

Default per-attempt timeout when no override is supplied.

Functions

build_resolver

Build a Hickory Resolver for a target with the target’s timeout.

classify_hickory_error

Map a Hickory error string into a stable ValidationFailureKind.

resolver_config

Build a ResolverConfig for a target.